Field
This present disclosure provides a method for spray tank cleanout. In particular, the disclosure further relates to a method for reducing residual sulfonylurea pesticide contamination of a spray tank from which the sulfonylurea is applied.
Description of Related Art
Sulfonylureas, as a class, are highly active pesticides. For this reason, it is desirable to clean out spray equipment before the equipment is subsequently used to treat crops sensitive to the sulfonamide herbicide used in the previous application. Adequate cleanout may require a rinsing procedure that is time-consuming and results in wastewater requiring proper environmental disposal. Furthermore, cleanout can be affected if the spray equipment contains organic deposits remaining from previous crop protection chemical applications or from other chemicals tank-mixed with the sulfonamide herbicide composition.
PCT patent application publication WO93/16596 describes a method for reducing residual sulfonylurea herbicide contamination of spray equipment by requiring as the first step the formulation of the sulfonylurea active ingredient in the form of an agriculturally suitable water soluble salt. The method for reducing residual sulfonylurea pesticide contamination of a spray tank from which the sulfonylurea is applied, comprising the steps: i) formulating the sulfonylurea the steps: agriculturally suitable water soluble salt composition before spray tank application, thereby increasing solubility of the sulfonylurea and decreasing the amount of insoluble sulfonylurea available for residual contamination of the spray tank; ii) applying the sulfonylurea salt composition to the crop while minimizing buildup of insoluble sulfonylurea in the spray tank; and (iii) rinsing the spray tank substantially free of residual sulfonylurea, after application, in an operation in which the sulfonylurea remaining in the spray tank is reduced significantly versus the amount remaining when sulfonylurea is not formulated as a water-soluble salt before application. But this method has disadvantages. In the tank cleanout protocol I, step 4, step 5, step 6, and step 7 all mentioned a cleaning solution. The cleaning solution can be water, or an ammonium hydroxide, or sodium hypochlorite solution. Especially in step 7, ammonium hydroxide solution was used. So even using sulfonylurea water soluble salt in the composition, washing the spray equipment with the cleaning solution was also necessary after finishing spraying.